Method of making refractory articles.



No. 884,463. I PATENTBD APR. 14, 1908. G. F. BURGBSS. METHOD OF MAKING REFRACTORY ARTICLES.

APPLIOATION FILED HAY 31,1906.

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PATENT o FIoE.

CHARLES F. BURGESS, OF MADISON, WISCONSIN. I

METHOD OF MAKING REFRACTORY ARTICLES.

Specification of Letters Patent.

Patented April 14, 1908.

Application nice May 31, 1906. Serial No. 319,598.

To all whom "it may concern: Be it known that I, CHARLES F. Bosonss, a citizen of the United States, residing at Madison, in the county of Dane and State of Wisconsin, have invented certain new and useful. Improvements in Methods of Making Refractory Articles, of which the following is a s wcification.

'lhis invention is a method of producing articles of refractory material and more ar ticularly such articles as require for t ie'ir j effective treatment the use of an electric furnace.

The method consists in forming the article. w1th or without a bonding material, and heating the same to'such temperature as may be required, usually to a temperaturesuflicient to fritor fuse together the constituent particles. During the heating the surface of the article is preferably defined by means of a layer of material which differs inv character from the article to be produced and which, after the heating, permits the clean so aratlon of the article by preventing the a herenceof adjacent articles or of portions of the adjacent charge.

T: method will described as applied has of magnesia in the form of crutubes' rbriclzs, but it not restricted ti. or to any p.=

tion' illustrating the method as applied to the manufacture of tubes; and Fig. 4 is a transverse vertical section of an electric furnace illustrating the a lication of the method to the roduction ot iiricks and other forms.

Figs. 1 and 2 illustrate an arrangement of a paratus suited for the production of crucibles or other vessels of magnesia or other refractory material. In said figures 1, 1 represent vessels of refractory material such as carbon containing a charge 2 of the material to be treated, consisting in the present instance of magnesia in a state of substantial purity. Centrally disposed 1n sa d charge is a conductor 3 of carbonor graphlte ofslzeand shape conforming to the interior of the:

'vessel to be produced and so constructed as nar form or As shown, the resistor 3 comgraphite blocks or conductors 6, 6, in such manner as to make effective electrical contact therewith. The current, applied through the terminal conductors 6, traverses the several resistors, as will be readily understood. o

In the production of articles in the ap aratus as above described, the surfaces a jacent to the source of heat are sufliciently smooth and regular, but the surfaces remote front-the resistor are usually quite irregular in contour, owing either to diifere'nces in the heat development in different portions of the resister or to differences in the heat conduc tivity of the charge. I have found that this objection can be overcome by defining the surface of the article to be produced by means of a layer of material indicated at 7, said material differing in character from the charge. If heat be applied to the charge to fuse 'orLfrit the constituent particles of the same, such fusion or fritting being carried to or .beyond the boundaries defined by the layer 7, it will be found that the portions of material outside of the surface marked or de fined by the layer 7 are readily separable at such surface, the result being that the contour of the article conforms to the original position of the layer 7.

, I do not limit myself to any articular material for the layer 7, though Fprefcr to use paper or other combustible or carbonizable material, and I find that by the use of such material aformed article having smooth and regular surfaces may be'readily prepared.

Fig. 3 illustrates the applicationof the method to the preparation of tubes of magnesia or other refractory material-.- 1 represents furnace walls inclosing a' chamber which is traversed by a carbon or graphite resister 3 corres onding in diameter to the packed a'roundthe resistor, the portion of the charge which is to constitute the finished tube being enveloped by'the layer-'7, referably ofpaper as above deseribec'l, eatii sga' applied to fuse or frit the magnesia Within I fractory material, which the limits defined by the layer 7 and usually i a surface of the article in a body of material. to some distance beyond the same, the heatof like character by IDCLHS of a layer of maing being such as to insure the effective 1 terial differing therefrom in character, and treatment of all material within these limits; applying heat to produce the article, subthe tube may thereafter be removed and any i stantially as described. adherent loose or fused or fritted material 1 2. The method of producing'art'cles of reseparated as above described. 1 fractory material, which consists in definin Fig. 4 illustrates the'method as ap lied to a surface of the article in a body of material the manufacture of refractory artic es such of like character by means of a layer of caras bricks or blocks. These are first molded bonizable material, and appl ing heat to roor otherwise formed of the dimensions reduce the article, substantially as descri ed. quired, any of the usual bonding materials i 3. The method of producing articles of re.- being used if desired, and are then stacked in fractory material, which consists in defining an electric furnace adjacent to resisters 3, a surface of the article in a body of material the articles being separated by layers 7 of i of like character by means of alayer of paper, ipaper or wrapped therein as indie ated in the q and ap lying heat to produce the article, subgure. The articles may be surrounded and stantia ly as described. covered by a loose body of the same material 1 4. The method of. producing articles. of as indicated at 8. i The layer 7 serves as bemagnesia, which consists in first molding or fore to permit a clean and free separation of otherwise forming the article and then applythe articles, and to prevent Welding thereto ing su fiicienaheat to frit or fuse together of adjacent articles or of adjacent portions of the constitutent particles, substantially as the walls or loose charge. described. 1

It will be understood that the method as 5. The method of forming articles of reillustrated by Fig. 3 is applicable to articles fractory material, which consists in first of any contour, such articles being prefermolding or otherwise forming the article, apably bedded in a body of loose refractory maplying a layer of material difiering thereterial. In case the articles are first molded rom in character to a surface thereof, and or shaped into the form required the layer 7 applying suflicient heat to frit or fuse tomay obviously be a plied in the form of a gether the constituent particles, substancoating of aint, difiermg 1n character from tially as described. the body 0 the article, and serving to define In testimony whereof, I aflix my signature the surface of the article and capable of preventing the adherence or welding thereto of in presence of two witnesses.

- CHARLES F. BURGESS.

adjacent materials.

I claim:-

1. The method of consists in defining \Vitnesses 'W. D. HIESTAND,

MAGDALEN EVANS.

producing articles of re- 

